Composite light weight building panel and core material therefor

ABSTRACT

A core material for a composite light weight building panel formed from a settable mixture, said mixture including an acrylic, polymer-based resin comprising:
         85% by volume water based copolymer emulsion of polyvinyl acetate with versatate and/or acrylic copolymers in a water emulsion;   10% water soluble colloid protector;   5% additives;
 
such that the resin obtains a specific gravity in the range of 1000±50 g/l and an 8 Ford viscosity at 20° C. of 7±1: and the mixture having the following ratios:
   from 1 to 3 liters of cement;   more than 2 liters of resin;   from 10 to 100 liters of light weight filler material;   less than 6 kilograms of water, and   such that the volume of cement is more than half the volume of resin.

CONTINUING DATA INFORMATION

This application claims priority to PCT Patent Application Serial No.PCT/AU01/00945 filed Aug. 3, 2001 which claims priority to AU PatentApplication Serial No. PQ 9210 filed Aug. 4, 2000.

TECHNICAL FIELD OF THE INVENTION

THIS INVENTION relates to a composite light weight building panel and acore material therefor.

BACKGROUND ART

The invention has been developed primarily for use in the constructionof dwelling houses and will be described with reference to thisapplication. However, it will be appreciated that the invention is notlimited to this particular field of use and may be used, for example, inthe construction of other buildings.

The core used for light weight panels is often made from foamed plasticsmaterial, such as polystyrene foam, and frequently includes suitablefire retardant additives. However, such foamed plastics materials areexpensive and of limited strength, and often rely upon cladding or acoating to impart strength to the panel. Sometimes composite panels havea metal cladding which increases their cost. Metal clad panels may alsobe difficult to cut to size, especially on a house constructions site.

The present invention aims to ameliorate one or more of the aboveproblems or at least provide an alternative composite wall panel and acore material therefor for use in building construction. Other aims andadvantages may become apparent from the following description.

DISCLOSURE OF THE INVENTION

With the foregoing in view, the present invention resides broadly,according to one aspect thereof, in a core material for a compositelight weight building panel formed from a settable mixture, said mixtureincluding an acrylic, polymer-based resin comprising:

85% by volume water based copolymer emulsion of polyvinyl acetate withversatate and/or acrylic copolymers in a water emulsion;

10% water soluble colloid protector;

5% additives;

such that the resin obtains a specific gravity in the range of 1000±50g/l and an 8 Ford viscosity at 20° C. of 7±1; and the mixture having thefollowing ratios;

from 1 to 3 liters of cement;

more than 2 liters of resin;

from 10 to 100 liters of light weight filler material;

less than 6 kilograms of water, and

such that the volume of cement is more than half the volume of resin.

Suitably, the additives include glycols, mildew agents, foamsuppressant, colouring agents, setting agents, wetting agents and/ordispersants, and preferably the copolymer emulsion comprises (dry)approximately 70% polyvinyl acetate, approximately 29% vinyl versatateand 1% acrylic acid. One preferred copolymer emulsion comprises (dry)69.3% polyvinyl acetate, 29.7% vinyl versatate and 1% acrylic acid, thepolymers comprising 45.5% of the emulsion, the balance being water. Itwill be appreciated by the addressee skilled in the art of aqueouspolymer emulsions that the copolymer emulsion and its additives may bevaried in its composition whilst providing a polymer-based resin whichwill set in normal atmospheric conditions.

Preferably, the acrylic, polymer-based resin is of the type identifiedby the trade mark “JOLLY FIX” as the product of Colorifico A. & B.Casati S.p.A of Verona, Italy, having their Product Code 109001, andhaving as one of its components 2-methyl-2,4-pentanediol. This productis an acrylic, polymer-based liquid resin (or powdered form if desired)currently sold in 16 liter containers, designed for use as a masonrysealer, the normal instructions being to dilute the product with waterand then paint it over the masonry for sealing purposes. An alternativesource of this material is Prima Enterprises Pty Ltd of Brisbane,Australia having their product code “J Fix 101”. Its use in the presentinvention, with unexpected results, and in novel proportions, meets alongstanding demand for products of this type having desirablecharacteristics.

In another aspect, the invention resides broadly in a core material fora composite light weight building panel formed from a settable mixture,said mixture including an acrylic, polymer-based resin as hereinbeforedescribed and having the ratios:

from 1 to 1½ liters of cement;

from 2 to 4 liters of resin;

from 60 to 100 liters of light weight filler material:

less than 2 kilograms of water.

Preferably, the consistency of the mixture is paste-like, and may bethixotropic such that the mixture may be formed into the shape of apanel core with the aid of vibration. It is also preferred that thepanel core is substantially planar having two opposite spaced apartfaces. In such form, it is further preferred that the core materialincludes a backing sheet, such as fibro cement, plywood, or paper.

In a preferred form, the mixture has the following ratios:

6 liters of resin;

4 liters of water;

8 liters of cement, and

from 60 to 100 liters of light weight filler material.

Preferably, the light weight filler material is in the form ofpolystyrene foam beads of approximately 3 mm diameter. However, otherfiller materials have been found to provide alternatives, includingminerals, such as perlite, vermiculite, or similar minerals, papercomminuted to short or long strips, or sawdust. The ratios of solidsmaterials (cement and light weight filler material) and liquid materials(water and resin) are selected to produce a core forming composition ofpaste-like consistency when mixed together, and which may be formed intoa desired shape, particularly, a planar panel-like shape, and allowed toset to form a core panel.

If additional strength is required, up to 40 g short strand fibreglassmay be added to the mixture. Additionally, fibreglass textile sheet maybe included within the core panel, approximately medially between thetwo faces, the fibreglass being added to the core panel in accordancewith a method according to the invention described hereinafter.

In a further preferred form, the core panel is coated with a coatingcomposition comprised in a mixture of sand or equivalent material,standard quality cement, water, and an acrylic, polymer-based resin ashereinbefore described, the mixture having the following ratios:

for every kilogram of sand:

more than 20 volume percent (vol %) cement; less than 12 vol % water;and more than 20 volt resin;

such that the ratio of resin to water is more than four to one, and theratio of resin to cement is less than two to one.

The coating composition may be formulated without the water, but it ispreferred that the water is more than 4 volt of the sand.

In one example, the coating composition has the aforementionedingredients are used in the proportions by volume of 5 liters of resin;4 liters of cement, 20 kg (12 liters) of sand and 400 ml of water.However, in other Examples, the material formulation by volume rangeswithin the following:

Resin: 5 liters (plus 300% down to less 70%) Cement: 4 liters (plus 100%down to less 70%, or further down to none at all) Sand: 12 liters (plus100% down to less 50%) and Water: 300-500 ml (plus or minus 100%), alldepending on the temperature as described.

The ingredients for the coating may be mixed in any suitable container,such as of metal or plastics material, the easiest procedure being toplace the resin and water in the container and cause these to be mixedby stirring steadily, adding the cement and sand progressively, such asin a standard concrete mixer. However, provided thorough mixing isensured, all ingredients could be added simultaneously to the container.The mixed product should be used without being stored since it containsa cement component and will set in a reasonably short period of time,such as 12 hours when in mixed bulk form. However, if a film of water isplaced over the product in a container, it may be stored overnight forexample, being able to be re-mixed manually and used without loss ofefficiency.

The mixed product can be applied to the panels of the present inventionat a building site after the moulding has been fixed in place. It willthus be apparent that the coating composition can be used also as apatching compound, covering marks left by penetrable fasteners when suchprocedures are called for, and also usable for repair purposes in theevent of damage to a moulding or the unlikely event of delaminationoccurring. The coating composition may be used as a filler if repairsare needed to existing mouldings, even if such existing mouldings weremanufactured in accordance with the prior art.

The cement used may be any type of standard quality cement, but it hasbeen found that standard Portland cement, ivory or white, is effective.The sand used is preferably beach sand which is quite fine, but anysand-like substitute could be used, provided it has a generallycomparable grain size. It will be apparent that the key component is theresin product as hereinbefore described.

The coating composition may be applied to a panel of the presentinvention by manual spraying, mechanical spraying, or the panels may beimmersed into the coating composition. The coating composition could betrowelled on, or brushed on or sponged on. Preferably there is used amanual spray action employing a hand-held, standard domestic orindustrial hopper gun, spraying being arranged at various degrees andangles depending upon the size and shape of the moulding. This can beachieved by forward and backward movement alternately in thelongitudinal direction of the panel or by circular rotationprogressively in a spiral or equivalent circular-type motion until thedesired thickness of coating has been attained. An operator mayincorporate air-flow pressure and hand-trigger adjustment of the hoppergun to create the desired steady flow and ensure evenness of coating tothe polystyrene, the pressure in the compressor for spraying purposesbeing about 2.8±1.4 MPa (400±200 psi).

Because the coating composition is light in weight yet strong indurability, the coating thickness can be as small as 0.05 mm, but thepreferred thickness is 1 mm to 2 mm, and sometimes up to 10 mm or morewhere filling is required, preferably applied in successive operationsspaced in time. While the coatings are light in weight, they give asolid, more cement-like appearance in the final product. There can be aprice saving to the consumer since less material is applied forcomparable results, while there is the major advantage that delaminationshould not occur with these compositions. Most importantly, no primerwill be required for adequate adhesion and the resultant product will befound to offer good water-resistance characteristics. The coatingcomposition may also be formulated without sand.

In an alternative preferred form, the other face is coated with analternative coating composition comprising (by volume);

a primary portion of adhesive material formed from ethylene vinylacetate copolymer diluted with 0% to 21% acrylic paint and 0% to 8%water, and

a secondary portion of textile material at least partially embedded inthe primary portion.

Preferably, the textile material is substantially completely embedded inthe adhesive material, and more preferably, such that the textilematerial is completely wetted or saturated by the adhesive material. Itis preferred that the textile material be a fibreglass textile materialranging from a fibreglass tissue having a gram weight specification of40/300 g/m² to a fibreglass mesh having a gram weight specification of50/400 g/m².

Other coatings may be provided, such as render, followed by a finishingcoating, such as paint, granosite, or such like.

In another aspect, the present invention resides broadly in a buildingpanel having a backing sheet and a core formed from a core material ashereinbefore described bonded to the backing sheet, the core having acoatable face remote from the backing sheet, and a coating applied tothe coatable face for weatherproofing the panel.

Preferably, the coatable face is formed with a rough surface to permitthe coating to be keyed in. For example, a render coating forweatherproofing is preferably applied in such manner that the rendermaterial penetrates at least partially into the coatable face.

In another aspect, the present invention resides broadly in a method offorming a core for a light weight composite building panel, said methodincluding the steps of:

providing a quantity of water and resin in a ratio as hereinbeforedescribed, and mixing the water and resin together;

adding thereto and mixing in a quantity of cement in a ratio ashereinbefore described to the water and resin to produce a slurry;

adding thereto and mixing in a quantity of light weight filler materialin a ratio as hereinbefore described to produce a core formingcomposition;

forming the core forming composition into a panel shape, and

leaving the panel shaped core forming composition for a time sufficientto set into a core forming panel.

Preferably, the mixture is applied to a backing board of fibre-cement,plywood, polystyrene sheet or such like to an overall panel thickness offrom 30 mm to 100 mm. The panels are preferably of an industry standardsize, such as 2.45 meters by 600 mm or 800 mm. The method mayincorporate the step of adding a layer of fibreglass textile to a firstlayer of the mixture prior to setting thereof, and adding a second layerof the mixture to the first layer onto the fibreglass textile to embedthe fibreglass layer between the first and second layers of the mixture.If desired, the fibreglass textile may be pressed into the first layerof the mixture, or wetted with water, resin, or a mixture thereof, orpre-soaked with the mixture without the light weight filler material, todecrease the likelihood of air being entrapped in the fibreglasstextile.

The method may then include the steps of coating the core with one ormore of the coating compositions as hereinbefore described, and allowingthe coating or coatings to set. A coating suitable for external use maybe provided on one face according to the intended use of the finishedpanel.

The ingredients may be mixed in any suitable container, but preferablyare loaded into a high speed blender. Mixers of the type which have atumbling action are also suitable, such as concrete mixers.

BRIEF DESCRIPTION OF THE DRAWINGS

In order that the invention may be more readily understood and put intopractical effect, reference will now be made to the accompanyingdrawings which illustrate a typical application of a preferredembodiment of the invention, and in which:

FIG. 1 is a part sectional view of a panel according to the invention asinstalled in relation to a first type of concrete slab arrangement:

FIG. 2 is a part sectional view of a panel according to the invention asinstalled in relation to a second type of concrete slab arrangement:

FIG. 3 is a part sectional view of a panel according to the invention asinstalled in relation to a first soffit arrangement;

FIG. 4 is a part sectional view of a panel according to the invention asinstalled in relation to a second soffit arrangement;

FIG. 5 is a part sectional view of a panel according to the invention asinstalled in relation to a flush eave arrangement;

FIG. 6 is a part sectional view of a panel according to the invention asinstalled in relation to a window sill: and

FIG. 7 is a part sectional view of a panel according to the invention asinstalled in relation to a window head.

DETAILED DESCRIPTION OF THE DRAWINGS

In the drawings, the same reference numerals are used to indicate thesame or corresponding parts, though not all such parts are givenreference numerals in each drawing. The panel 10 shown in each of FIGS.1 to 7 is fixed to a stud 21 by a several fixing brackets showntypically at 22 so that it is spaced therefrom. A wall lining 23 isfixed to the stud (and other parts of a building frame not shown).

The panel has an inner face closer to the stud and an outer face spacedtherefrom, and a reinforcing mesh 11 interposed between the faces. Theinner face has a backing membrane bonded thereto, and the outer face hasa render coating applied. The brackets are fixed to a channel 17embedded in the panel with its web against the inner surface and itsflanges extending into the body of the panel.

Referring to FIG. 1, the base of the panel rests on a silicone beadprovided on the upper face of a footing which supports a concrete slabwhich rests on in FIG. 2, the base of the panel rests on the upper faceof a step on the edge of the concrete slab which itself is supported ona footing, Referring to FIG. 3, the panel extends above the soffitlining 31, but in FIG. 4, the upper edge of the panel abuts against theunderside face of the soffit lining. Referring to FIG. 5, a facia board32 covers an upper strip of the outer face near the upper edge of thepanel.

Referring to FIGS. 6 and 7, the edges of the panel closest to the windowframes 42 are encased by an edge angle 45 with one flange embeddedbetween the render and the panel core, and the other flange forming theedge of the panel. A bead of sealant 44 is applied to seal the edge ofthe panel with respect to the window frames.

Although the invention has been described with reference to specificexamples, it will be appreciated by those skilled in the art that theinvention may be embodied in many other forms which fall within thebroad scope and ambit of the invention as defined in the followingclaims.

1. A settable mixture for use in a core material for a composite lightweight building panel, said mixture including an acrylic, polymer-basedresin comprising: 85% by volume water based copolymer emulsion ofpolyvinyl acetate with versatate and acrylic copolymers in a wateremulsion; 10% water soluble colloid protector; 5% additives; such thatthe resin obtains a specific gravity in the range of 100±50 g/l and an 8Ford viscosity at 20° C. of 7±1; and the mixture having the followingratios: from 1 to 3 liters of cement; more than 2 liters of resin; from10 to 100 liters of light weight filler material; less than 6 kilogramsof water, and such that the volume of cement is more than half thevolume of resin; and wherein the copolymer emulsion comprises 69.3%vinyl acetate, 29.7% vinyl versatate, and 1% acrylic acid, the polymerscomprising 45.5% of the emulsion, the balance being water.
 2. A settablemixture for use in a core material for a composite light weight buildingpanel, said mixture including an acrylic, polymer-based resin as definedin claim 1 and having the ratios: from 1 to 1½ liters of cement; from 2to 4 liters of resin; from 60 to 100 liters of light weight fillermaterial; less than 2 kilograms of water; and such that the volume ofthe cement is more than half the volume of the resin.
 3. A settablemixture for use in a core material according to claim 2, wherein theconsistency of the mixture is paste-like and is formed to besubstantially planar having two opposite spaced apart faces.
 4. Asettable mixture for use in a core material according to claim 3,wherein the further comprising a backing sheet, selected from fibrocement, plywood, and paper.
 5. A settable mixture for use in a corematerial according to claim 2, wherein the mixture has the followingratios: 6 liters of resin; 8 liters of cement, and from 60 to 100 litersof a light weight filler material; and wherein the mixture is dilutedwith 4 liters of water.
 6. A settable mixture for use in a core materialaccording to claim 5, wherein the ratios of solids materials (cement andlight weight filler material) and liquid materials (water and resin) areselected to produce a core forming composition of paste-like consistencywhen mixed together, and which may be formed into a desired shape.
 7. Asettable mixture for use in a core material according to claim 3, andfurther including a fibreglass textile sheet included within the corepanel, approximately medially between the two faces.
 8. A compositepanel including a core material formed from a settable mixture accordingto claim 1 and having two spaced apart faces.
 9. A composite panelincluding a core material formed from a settable mixture according toclaim 1, wherein the core material is coated with a coating compositioncomprising a mixture of sand, standard quality cement, water, and theacrylic, polymer-based resin as defined in claim 1, the mixture havingthe following ratios: for every kilogram of sand: more than 20 volumepercent (vol %) cement; less than 12 vol % water; and more than 20 vol %resin; such that the ratio of resin to water is more than four to one,and the ratio of resin to cement is less than two to one.
 10. Acomposite panel according to claim 9, wherein the coating composition isformulated without the water.
 11. A composite panel according to claim9, wherein the coating composition is formulated with water to more than4 vol % of the sand.
 12. A composite panel according to claim 9, whereinthe coating composition has the proportions by volume of 5 liters ofresin; 4 liters of cement, 20 kg (12 liters) of sand and 400 ml ofwater.
 13. A composite panel according to claim 8, wherein one of thespaced apart faces is coated with an alternative coating compositioncomprising (by volume): a primary portion of adhesive material formedfrom ethylene vinyl acetate copolymer diluted with 0% to 8% water, and asecondary portion of textile material at least partially embedded in theprimary portion.
 14. A composite panel according to claim 13, whereinthe textile material is embedded in the adhesive material, and such thatthe textile material is completely wetted or saturated by the adhesivematerial.
 15. A composite panel according to claim 13, wherein thetextile material is a fibreglass textile material ranging from afibreglass tissue having a gram weight specification of 40/300 g/m² to afibreglass mesh having a gram weight specification of 50/400 g/m².
 16. Abuilding panel having a backing sheet and a core formed from a corematerial which is formed from a settable mixture according to claim 1,the core bonded to the backing sheet, the core having a coatable faceremote from the backing sheet, and a coating applied to the coatableface for weatherproofing the panel.